1. Field of the Invention
This invention relates to apparatus for spinning of photoresist upon a work piece, and more particularly to optimizing the quantity of photoresist used.
2. Description of Related Art
In photolithography, photoresist (also usually referred to in the art as resist and referred to both ways herein interchangeably) is deposited upon a work piece to be patterned by the photolithographic process. The expense of the quantity of photoresist used is the most or nearly the most expensive part of the cost of the process currently, depending upon prices of the materials used. Unfortunately, conventional resist spinners waste expensive resist material. In an application to manufacturing of semiconductor wafers, for example, a thick film of photoresist in the form of a puddle millimeters in height is delivered to cover most of a semiconductor wafer. Then the surplus photoresist material is spun off the semiconductor wafer surface, leaving an ultimate thickness of photoresist which is only on the order of several micrometers on the surface of the wafer. A very economical process currently requires 5 ml of photoresist material for each six inch diameter wafer.
U.S. Pat. No. 4,800,836 of Yamamoto et al for "Resist Coating Apparatus" neither introduces nor removes vapor from the chamber in which the resist is dumped on the substrate. No spraying is employed and there is no delay after application.
U.S. Pat. No. 4,416,213 of Sakiya for "Rotary Coating Apparatus" does not control the environment of the deposited resist.
U.S. Pat. No. 4,290,384 of Ausschnitt et al for "Coating Apparatus" suggests use of a mist but no spray and no spinning.
Japanese J6001248-A 85.01.19 (8509) Fujitsu, describes a resist coating method in which the atmosphere of resist solvent vapor is formed adjacent a semiconductor substrate and the resist is coated onto the semiconductor substrate. The solvent is discharged from one side of a porous disc. The resist is dropped onto the substrate. There is no spraying and no savings in resist material.
Japanese J02113518A 90.04.25 (9023) Mitsubishi Denki KK describes a resist coating device with a circular passage to introduce resist mist at a place surrounding the wafer on a spin chuck.
Japanese J02100314A 90.04.12 (9021) NEC Corp. describes an inner wall cup to coat a film of solvent or gas of photoresist.
In accordance with this invention, apparatus for treating a polymer coated substrate comprises as follows:
a) a support for the substrate, PA1 b) an controlled chamber surrounding the substrate and the support, PA1 c) means for introducing a solvent vapor into the chamber and PA1 d) means for removing the solvent from the chamber. PA1 a) a support for the substrate, the support being rotatably supported for spinning, PA1 b) an enclosed chamber surrounding the substrate and the support, PA1 c) means for introducing a solvent vapor into the chamber, and PA1 d) means for removing the solvent from the chamber comprising an evacuated chamber coupled with the enclosed chamber for removing the solvent vapor from the enclosed chamber. Preferably, the means for introducing includes means for vaporizing solvent, and the means for introducing the solvent vapor comprises at least one vaporizing nozzle, and the support is rotatably supported for spinning. PA1 a) a support for the substrate, PA1 b) a sealed chamber surrounding the substrate and the support, PA1 c) means for introducing a solvent vapor into the chamber, PA1 d) means for applying the polymer to the substrate, and PA1 e) means for removing the solvent from the chamber. PA1 a. applying a solvent enriching vapor upon a substrate, PA1 b. subsequently spraying the coating material upon the substrate, PA1 c. spinning the substrate, PA1 1. A spread out delay time is introduced between the spraying step and the spinning step. PA1 2. The coating material comprises resist. PA1 3. The substrate is spun at a high rpm during solvent vapor introduction. PA1 4. The substrate is spun at a substantially lower or zero rpm during introduction of coating material.
Preferably, the support is rotatably supported for spinning.
Further in accordance with this invention, apparatus for treating a polymer coated substrate comprises:
The means for introducing can comprise an auxiliary vapor chamber coupled with the enclosed chamber for providing the solvent vapor to the enclosed chamber, or the means for removing comprises an evacuated chamber coupled with the enclosed chamber for removing the solvent vapor from the enclosed chamber. At least one vaporizing nozzle is provided for vaporizing solvent vapor. The means for introducing can comprise an auxiliary vapor chamber coupled with the enclosed chamber for providing the solvent vapor to the enclosed chamber.
The apparatus for coating a substrate with a polymer or other material comprises:
Preferably, the support is rotatably supported for spinning. The means for introducing includes means for vaporizing solvent. The means for introducing the solvent vapor comprises at least one nozzle. In another embodiment the means for introducing the solvent vapor comprises at least one vaporizing nozzle and the support is rotatably supported for spinning. Alternatively, the means for introducing comprises an auxiliary vapor chamber coupled with the enclosed chamber for providing the solvent vapor to the enclosed chamber.
The means for removing comprises an evacuated chamber coupled with the enclosed chamber for removing the solvent vapor from the enclosed chamber. The means for applying the polymer comprises a spraying nozzle. Preferably, the means for applying the polymer comprises a plurality of spraying nozzles, which preferably are oriented obliquely.
A process of spin coating a soluble coating material upon a substrate comprising
whereby thickness and uniformity are controlled.
Preferably, the process includes features as follows:
After a step of thickness regulating spinning, a delay time is introduced before a step of solvent vapor evacuation.
During the spinning step and a spread out delay time, vapor pressure of the solvent enriching vapor is maintained substantially stable.
During the spinning step, solvent vapor pressure is substantially reduced by exhaust thereof into an evacuation outlet.
Ultrasonic agitation is applied to the system, during the delay time, before spinning.
Vibratory agitation is applied to the system, during the delay time, before spinning.
In another embodiment, the nozzles are scanned.